Shock absorber



Oct. 25, 1932. F. D. FuNsToN 1,883,895

SHOCK ABSORBER Filed 001'.. 19, 1931 4 1f' z a 36 15.

31A/manto@ @9mm/m0. @wam/Y (H5601 nui( atentecl @et 25., i332 naarFREDERICK D. FUNSTON, OF DAYTON, OHIO, ASSIGNOR TO DELCO PRODUCTSCORPORA- TION, OF DAYTON, OHIO, .A CORPORATON F DELAWARE SHOCK ABSORBERApplication led October 19, 1931. Serial No. 569,704.

This invention relates to improvements in hydraulic shock absorbers.

lt is among the objects of the present invention to provide a hydraulicshock absorber with a fluid flow control device capable of beingadjusted manually or automatically', in accordance withtemperaturechanges.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawing wherein a preferred embodiment of one form of the presentinvention is clearly shown.

In the drawing:

Fig. 1 is a fragmentary side view of a vehicle chassis havingattached-thereto a shock absorber equipped with the present invention.

Fig. 2 is a sectional view taken longitudinally of the shock absorber,certain parts being shown in elevation for the sake of clearness.

Fig. 3 is a detail sectional view taken substantially along the line 3-3of Fig. 2.

Fig. 4 is a detail view of a portion of the Huid flow control device.

Fig. 5 is a view showing the shape ofthe orifice in the adjustable Huidflow control valve. Y

Referring to the drawing, the shock absorber is shown comprising acasing providing a fluid reservoir 21 and a cylinder 22. The ends of thecylinder are closed by cylinder head caps 23 and 24. Within the cylinderthere is provided a piston 25 forming compression chambers 26 and 27,the former being termed the spring compression control chamber, thelatter the spring rebound control chamber.

The piston operating arm or lever 30 is oscillatably supported upon ashaft 31 rotatably carried by the casing. One end of this shaft or rod31 extends outside the shock absorber casing and has the operating arm32 attached thereto, the free end of said arm being swivelly secured toone end of a link 33, the other-end of said link being swivelly attachedto a bracket 34 anchored to the vehicle axle 35 by a clamping member 36.The axle 35 supports vehicle springs 37, which in turn support thevehicle frame 38, as shown in Fig. 1.

The piston 25 within the cylinder 22 comprises two head portions andlll,each having a passage for the transfer of fluid from one side of thehead portion to the other, each piston in turn having fluid flow controlmechanism whereby when the piston is moved in one direction, asubstantially free flow of fluid willv be directed from the piston tothe reservoir into the compression chamber, while when the piston ismoved in the opposite direction a restricted How of Huid is establishedfrom the compression chamber into the reservoir upon a predeterminedliuid pressure having been reached. y l

inasmuch as the fluid How control mechanism of each piston head is thesame, only one will be described forthe sake of brevity. y

Referring to the piston head portion 41 which is shown in Fig. 2, thenumeral designates the fluid passage therein about which there isprovided an annular ridge forming a valvel seat 51. A. cage member 52 issecured within the piston in any suitable manner. rlhe valve forestablishing a substantially free flow of uid from the reservoir 21 intothe chamber 27 is designated by the numeral 53 and is urged intoengagement with the valve seat 51 by the spring 54. The valve forestablishing a restricted How of Huid from the compression chamber intothe reservoir in response to the movement of the piston in anotherdirection, comprises a tubular member 55 slidably supported by the valve53 and hav- .ing a head portion 56 yieldably urged into engagement withthe outer surface of the valve 53 by a spring 57. In the head 56 of thevalve there is a through passage 58 leading to an annular groove 59 inthe end surface of valve head 56. A spring disc 60, secured on the valvehead 56 and centrally thereof in any suitable manner, yieldably closesthe annular groove 59.

As the spring 37 is moved toward the frame 38, which is its compressionmovement, due to the road wheels of the vehicle striking an obstructionin the roadway, the link 33 and arm 32 will rotate shaft 31 and its armor lever 30 clockwise as regards Figs. l and 2 Y:as

and thus the piston 25 is moved toward the left. Fluid within thechamber 26 will have pressure exerted thereupon. Fluid from thereservoir 21 will, in response to this piston movement, urge valve 53from its seat against the effect of spring 54 to establish asubstantially free flow of fluid into the spring rebound control chamber27.

The return of the vehicle spring 37 toward its normal load positioncauses the lever connections with arm 30 to move said armcounter-clockwise, thus to move the piston 25 to the right as regardsFig. 2. Now the fluid within the spring rebound control chamber 27 haspressure exerted thereupon which, having attained a proper degree, willbe exerted through the valve 55, through its passage 58 in the head 56to flex the disc 60 so as to establish a flow from passage 58, annulargroove 59 into the reservoir 21. This flow being restricted will resistthe movement of the pist0n toward the right and likewise the reboundingmovement of the vehicle springs 37 will be resisted. Excessive fluidpressures in chamber 27 will move valve 55 bodily relatively to thevalve 53 and thus there will be established a fluid flow through theopening 62 in the side of the valve 55 which opening normally is closedbecause it normally lies within the confines of the valve 53.

The present shock absorber is provided with means for by-passing fluidfrom the chamber 27 around the piston to the reservoir 21 therebytoestablish a flow from said chamber to said reservoir before either oneof the valves or 55 establish their restricted flows. This by-passcomprises a duct 70 in the casing leading into a counterbore 80 whichopens to the outside of the shock absorber. The outer end of thiscounterbore is interiorly threaded as at 81. A cross passage 82 providescommunication between the counterbore portion 80 of duct 70 and thereservoir 21, as shown in Fig. 2. The threaded end of duct 70, or moreparticularly its counterbored portion, receives a recessed plug 83. Theouter end of thisl plug has a central opening 84 through which extendsthe actuator 85 which has an annular flange 86 fitting within the recessof the plug 83. A suitable packing 87 is provided about the actuator 85within the recessed plug 83 to prevent leaks at this point.

A pointer 88 is provided on the actuator 85 to indicate the degree ofmanual adjustment of said actuator.

Within the counterbored portion 80 of the duct 70 there is press-fitteda sleeve 90, having an annular groove 91 so located that it willcommunicate with cross passage 82 when the sleeve 90 is in position inthe duct 7 O. A

comparatively narrow, longitudinal slot 92 is cut through the wall ofthe sleeve 90 to provide communication between the annular groove 91 andthe interior of the sleeve 90. A valve 94, of tubular construction, isrotatably carried within the sleeve 90. As shown in Fig. 5, this valvehas a tapering slot 95 cut therein, one end of the slot being of greaterwidth than the other. This slot extends transversely ofthe slot 92 inthe sleeve 90 whereby, upon rotation of the valve 94 relative to thesleeve, the cross sectional area of slot 95 communicating with slot 92may be varied. This valve arrangement is not affected by fluid pressureinasmuch as variations in the orifice are obtainable only by turningvalve 94.

A `bi-metallic strip 96, shown to be wound helically has its one endanchored to the actuator member 85, the opposite end being anchored tothe valve 94. This helically wound piece of bi-metal provides not only amechanical connection between the actuator 85 and the valve 94 wherebythe valve 94 will be caused to rotate with the actuator 85 when it isturned for adjustment purposes, but it also provides an automa-tic meansfor adjusting the valve 94 so that said valve is rotated in response to,and in accordance with, variations in temperature of the fluid passingthrough the duct 70. It will, of course, be understood that'the bi-metalmember 96 acts automatically independent of the operation of theactuator 85.

As the piston head portion 41 moves to exert pressure upon the fluidwithin the spring rebound control chamber 27, the fluid will be causedto flow through duct 70, through the valve 94 and its transverse slot95, thence through the longitudinal slot 92 in sleeve 90, into theannular groove, thence through cross passage 82 into the reservoir 21.If the operator finds that this flow of fluid is not sufficientlyrestricted, that is if the restriction to the flow of fluid 'is suchthat too free a ride is permitted by the shock absorbers, then theactuator 85 is turned, causing the bi-metal strip 96 now acting as amechanical connection, to turn valve 94 so that a narrower portion ofits slot 95 is brought into communication with the longitudinal slot 92of the sleeve 90. If, on the other hand, the shock absorbers too greatlyresist spring or body movements and thereby provide too still' a ride,then the actuator 84 is operated to rotate the valve so that a widerportion of its slot 95 is presented to the longitudinal slot 92 ofsleeve 9() whereby the fluid flow through duct will be restricted at alesser degree and consequently the shock absorbers will offer a softerride by decreasingly resisting spring and body movements.

If the temperature ofthe fluid within the u shock absorber issubstantially reduced, thereby causing the viscosity of the oil toincrease, due to which restriction to the fluid flow in the by-pass duct7 0 is increased excessively, the bi-metal strip 96 will, in response tosuch lower temperature Aof fluid,v

operate to rotate valve 94 so that a wider portion of its transversepassage 95 will be prelessees? sented to the longitudinal slot 92 oisleeve 90, whereby to reduce therestrict-ion to the luid flow andthereby automatically adjust the shock absorber to compensate for theincreased viscosity of its fluid. 'lhe reverse is true if the viscosityof the fluid is suddenly decreased, under which condition the bi-nietalstrip 96 will operate to increase fluid ilow restriction through theslots and 92, respectively.

ln the present invention applicant has provided a shock absorber adaptedto be adj usted manually and automatically to vary its characteristics,a common member being provided which, for manual adjustment acts as a.mechanical connection, but which is adapted to act automatically toobtain the proper adjustments of the fluid flow control device iiiaccordance with temperature changes and irrespective of pressures.

While the form of embodiment of the present invention as hereindisclosed, constitutes a preferred form, it is to be understood thatother forms might be adopted, all coming within the scope of the claimswhich follow.

lll/'hat is claimed is as follows:

l. A shock absorber comprising, in combination, a casing providing afluid reservoir and a cylinder; a piston in said cylinder forming acompression chamber therein; a piston operating member; a duct in thecasing connecting the compression chamber with the uid reservoir; avalve in said duct comprising two telescppically engaging tubularmembers, one of which is stationary the other rotatable relatively tosaid stationary member, both members having openings adapted to align;an actuator in said duct, extending outside the casing; and athermostatic element connected to the actuator and the rotary valvemember, said element being adapted automatically to rotate the valve inresponse to temperature changes to disalign the holes in the valvemembers and thus vary the flow of luid through the duet in accordancewith said temperature changes, said thermostatic element being adaptedalso to adj ust the valve in response to adjustments of the actuator.

2. A shock absorber comprising, in combination, a casing providing aiiuid reservoir and cylinder; a piston in said cylinder forming acompression chamber therein; a piston operating member; avalve adaptedlto establish a restricted flow of fluid from the compression chamberinto the reservoir in response to movements of the piston in onedirection, said valve comprising two telescopically engaging tubularmembers having normally aligned openings, one member being stationarythe other being rotatably supported thereby; an actuator accessible fromoutside the shock absorber and manually operable to adjust the rotaryvalve member for varying the restriction to the flow of fluid; and atemperature responsive member connected between the actuator and therotary valve member for transmitting motion from the actuator to therotary valve member and adapted automatically to adjust said valvemember in response to and in accordance with temperature changes.

3. A shock absorber comprising, in cenibination, a casing providing afluid reservoir and a cylinder in which a iiuid compression chamber isformed by a reciprocative piston; a duct providing for the escape oflluid from said chamber; a rotary valve in said duct for restricting theHow of fluid therethrough; a manually operable actuator; and abi-metallic member providing an operative connection between theactuator and valve for rotating said valve in response to operation ofthe actuator and also for rotating said valve in response t'o and inaccordance with temperature changes, independently of the operation otthe actuator.

4. In a hydraulic shock absorber of the piston and cylinder type, thecombination with a fluid compression chamber therein; a fluid exhaustduct; a sleeve in said duet having a port therein; a rotary valve insaid sleeve cooperating with the port to restrict the low of fluidthrough the duct; a manually operable valve adjusting member; and ateinperature responsive element operatively connecting the said memberwith the valve so that said valve is rotatable with said member saidelement, however, being adapted automatically to rotate the valve inresponse to and in accordance with temperature changes independently ofthe operation of the manuallyv operable member.

5. A- shock absorber comprising, in combination, a casing providing aHuid reservoir and a cylinder; a piston in said cylinder forming acompression chamber therein; a piston operating member; a .duct in thecasing leading from the compression chamber to the outside of thecasing, said duct having a counter-bored portion interlorly threaded atthe outer end; a cross passage connecting the duct and fluid reservoir;a recessed plug in-the threaded end of the,duct, said plug having acentralv opening; a sleeve litting snugly into the counter-bored portionof the duct and extending into the recess of the plug, said sleevehaving an outer, annular groove aligning with the cross passage and tothe tubular' valve and adapted to rotate said valve relative to thesleeve when the actuator is rotated, and also adapted automatically torotate said valve in response to 5 and in accordance with thetemperature variations of the Huid Within the casing. v

6. Ashock absorber comprisin in combination, a casing providing a uidreservoir and a cylinder; a piston in said cylinder formingv acompression chamber therein; a,

piston operating member; a duct in the casing leading from thecompression chamber to the outside of the casing, said duct having acounter-bored portion threaded at the outer end; a cross passageconnecting the duct and fluid reservoir; a

recessed pIug in the threaded end of the duct,

' said plug having a central opening; a. sleeve fitting snugly into thecounter-bored portion of the duct and extending into the recess of theplug said sleeve having an outer, annular groove aligning with the crosspassage and a comparatively narrow, longitudinal slot providingcommunication between the annular groove and the interior of saidsleeve; a tubular valve rotatably supported Within the sleeve said valvehaving a tapering transverse slot registering with the 1ongitudinalslotl in the sleeve; an actuator exso tending through the centralopening in the screw plug into the recess therein; a packing in therecess of the plug about the actuator; and a helically Wound strip ofbimetal attached to the actuator at one end and to the tubular valve atthe opposite end and providing a mechanical connection between the valveand actuator so the rotation of the latter Will be transmitted to thevalve, said bi-metal strip exerting a twisting effort upon the valve toturn it in response to and in accordance with varying temperatures ofthe fluid in the duct, independently of rotation ofthe actuator.

7. In a hydraulic shock absorber having a casing providing a fluidreservoir and a cylinder in which a piston forms a compression chamberthe combination with a duct leading from the said chamber to the outsideof the shock absorber; a cross passage connect- B01 ing the duct withthe fluid reservoir; arecessed plug secured in the outer end of the ductand having a central opening; a sleeve press fitted into the duct saidsleeve having a slot through its Wall in communication with the crosspassage; a tubular valve rotatably carried in said sleeve and having aslot transversely of the slot in the sleeve With which it communicates,one of said slots being comparatively narrow, the other varying inwidth; an actuator extending through the opening' in theplug into therecess therein; a packing in said recessed plug around the actuator; anda helically Wound, bi-metal strip attached at one end to the actuatorand 85 at the other end'to the valve, forming a meinteriorly peraturesindependently of actuator adjustments.

In testimony whereof I hereto affix my signature.

FREDERICK D. FUNSTON.

